Index: cfe/trunk/lib/CodeGen/CGExprConstant.cpp =================================================================== --- cfe/trunk/lib/CodeGen/CGExprConstant.cpp +++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp @@ -22,6 +22,8 @@ #include "clang/AST/RecordLayout.h" #include "clang/AST/StmtVisitor.h" #include "clang/Basic/Builtins.h" +#include "llvm/ADT/Sequence.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Function.h" @@ -30,345 +32,636 @@ using namespace CodeGen; //===----------------------------------------------------------------------===// -// ConstStructBuilder +// ConstantAggregateBuilder //===----------------------------------------------------------------------===// namespace { class ConstExprEmitter; -class ConstStructBuilder { - CodeGenModule &CGM; - ConstantEmitter &Emitter; - - bool Packed; - CharUnits NextFieldOffsetInChars; - CharUnits LLVMStructAlignment; - SmallVector Elements; -public: - static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, - ConstExprEmitter *ExprEmitter, - llvm::Constant *Base, - InitListExpr *Updater, - QualType ValTy); - static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, - InitListExpr *ILE, QualType StructTy); - static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, - const APValue &Value, QualType ValTy); - -private: - ConstStructBuilder(ConstantEmitter &emitter) - : CGM(emitter.CGM), Emitter(emitter), Packed(false), - NextFieldOffsetInChars(CharUnits::Zero()), - LLVMStructAlignment(CharUnits::One()) { } - - void AppendField(const FieldDecl *Field, uint64_t FieldOffset, - llvm::Constant *InitExpr); - - void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst); - - void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, - llvm::ConstantInt *InitExpr); - void AppendPadding(CharUnits PadSize); - - void AppendTailPadding(CharUnits RecordSize); - - void ConvertStructToPacked(); +struct ConstantAggregateBuilderUtils { + CodeGenModule &CGM; - bool Build(InitListExpr *ILE); - bool Build(ConstExprEmitter *Emitter, llvm::Constant *Base, - InitListExpr *Updater); - bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase, - const CXXRecordDecl *VTableClass, CharUnits BaseOffset); - llvm::Constant *Finalize(QualType Ty); + ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {} CharUnits getAlignment(const llvm::Constant *C) const { - if (Packed) return CharUnits::One(); return CharUnits::fromQuantity( CGM.getDataLayout().getABITypeAlignment(C->getType())); } - CharUnits getSizeInChars(const llvm::Constant *C) const { - return CharUnits::fromQuantity( - CGM.getDataLayout().getTypeAllocSize(C->getType())); + CharUnits getSize(llvm::Type *Ty) const { + return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(Ty)); } -}; - -void ConstStructBuilder:: -AppendField(const FieldDecl *Field, uint64_t FieldOffset, - llvm::Constant *InitCst) { - const ASTContext &Context = CGM.getContext(); - - CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset); - - AppendBytes(FieldOffsetInChars, InitCst); -} - -void ConstStructBuilder:: -AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) { - assert(NextFieldOffsetInChars <= FieldOffsetInChars - && "Field offset mismatch!"); - - CharUnits FieldAlignment = getAlignment(InitCst); - - // Round up the field offset to the alignment of the field type. - CharUnits AlignedNextFieldOffsetInChars = - NextFieldOffsetInChars.alignTo(FieldAlignment); - - if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) { - // We need to append padding. - AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars); - - assert(NextFieldOffsetInChars == FieldOffsetInChars && - "Did not add enough padding!"); + CharUnits getSize(const llvm::Constant *C) const { + return getSize(C->getType()); + } - AlignedNextFieldOffsetInChars = - NextFieldOffsetInChars.alignTo(FieldAlignment); + llvm::Constant *getPadding(CharUnits PadSize) const { + llvm::Type *Ty = CGM.Int8Ty; + if (PadSize > CharUnits::One()) + Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity()); + return llvm::UndefValue::get(Ty); } - if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) { - assert(!Packed && "Alignment is wrong even with a packed struct!"); + llvm::Constant *getZeroes(CharUnits ZeroSize) const { + llvm::Type *Ty = llvm::ArrayType::get(CGM.Int8Ty, ZeroSize.getQuantity()); + return llvm::ConstantAggregateZero::get(Ty); + } +}; - // Convert the struct to a packed struct. - ConvertStructToPacked(); +/// Incremental builder for an llvm::Constant* holding a struct or array +/// constant. +class ConstantAggregateBuilder : private ConstantAggregateBuilderUtils { + /// The elements of the constant. These two arrays must have the same size; + /// Offsets[i] describes the offset of Elems[i] within the constant. The + /// elements are kept in increasing offset order, and we ensure that there + /// is no overlap: Offsets[i+1] >= Offsets[i] + getSize(Elemes[i]). + /// + /// This may contain explicit padding elements (in order to create a + /// natural layout), but need not. Gaps between elements are implicitly + /// considered to be filled with undef. + llvm::SmallVector Elems; + llvm::SmallVector Offsets; + + /// The size of the constant (the maximum end offset of any added element). + /// May be larger than the end of Elems.back() if we split the last element + /// and removed some trailing undefs. + CharUnits Size = CharUnits::Zero(); + + /// This is true only if laying out Elems in order as the elements of a + /// non-packed LLVM struct will give the correct layout. + bool NaturalLayout = true; + + bool split(size_t Index, CharUnits Hint); + Optional splitAt(CharUnits Pos); + + static llvm::Constant *buildFrom(CodeGenModule &CGM, + ArrayRef Elems, + ArrayRef Offsets, + CharUnits StartOffset, CharUnits Size, + bool NaturalLayout, llvm::Type *DesiredTy, + bool AllowOversized); - // After we pack the struct, we may need to insert padding. - if (NextFieldOffsetInChars < FieldOffsetInChars) { - // We need to append padding. - AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars); +public: + ConstantAggregateBuilder(CodeGenModule &CGM) + : ConstantAggregateBuilderUtils(CGM) {} - assert(NextFieldOffsetInChars == FieldOffsetInChars && - "Did not add enough padding!"); - } - AlignedNextFieldOffsetInChars = NextFieldOffsetInChars; + /// Update or overwrite the value starting at \p Offset with \c C. + /// + /// \param AllowOverwrite If \c true, this constant might overwrite (part of) + /// a constant that has already been added. This flag is only used to + /// detect bugs. + bool add(llvm::Constant *C, CharUnits Offset, bool AllowOverwrite); + + /// Update or overwrite the bits starting at \p OffsetInBits with \p Bits. + bool addBits(llvm::APInt Bits, uint64_t OffsetInBits, bool AllowOverwrite); + + /// Attempt to condense the value starting at \p Offset to a constant of type + /// \p DesiredTy. + void condense(CharUnits Offset, llvm::Type *DesiredTy); + + /// Produce a constant representing the entire accumulated value, ideally of + /// the specified type. If \p AllowOversized, the constant might be larger + /// than implied by \p DesiredTy (eg, if there is a flexible array member). + /// Otherwise, the constant will be of exactly the same size as \p DesiredTy + /// even if we can't represent it as that type. + llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const { + return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size, + NaturalLayout, DesiredTy, AllowOversized); } +}; - // Add the field. - Elements.push_back(InitCst); - NextFieldOffsetInChars = AlignedNextFieldOffsetInChars + - getSizeInChars(InitCst); - - if (Packed) - assert(LLVMStructAlignment == CharUnits::One() && - "Packed struct not byte-aligned!"); - else - LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment); +template> +static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) { + assert(BeginOff <= EndOff && "invalid replacement range"); + llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals); +} + +bool ConstantAggregateBuilder::add(llvm::Constant *C, CharUnits Offset, + bool AllowOverwrite) { + // Common case: appending to a layout. + if (Offset >= Size) { + CharUnits Align = getAlignment(C); + CharUnits AlignedSize = Size.alignTo(Align); + if (AlignedSize > Offset || Offset.alignTo(Align) != Offset) + NaturalLayout = false; + else if (AlignedSize < Offset) { + Elems.push_back(getPadding(Offset - Size)); + Offsets.push_back(Size); + } + Elems.push_back(C); + Offsets.push_back(Offset); + Size = Offset + getSize(C); + return true; + } + + // Uncommon case: constant overlaps what we've already created. + llvm::Optional FirstElemToReplace = splitAt(Offset); + if (!FirstElemToReplace) + return false; + + CharUnits CSize = getSize(C); + llvm::Optional LastElemToReplace = splitAt(Offset + CSize); + if (!LastElemToReplace) + return false; + + assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) && + "unexpectedly overwriting field"); + + replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C}); + replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset}); + Size = std::max(Size, Offset + CSize); + NaturalLayout = false; + return true; } -void ConstStructBuilder::AppendBitField(const FieldDecl *Field, - uint64_t FieldOffset, - llvm::ConstantInt *CI) { +bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits, + bool AllowOverwrite) { const ASTContext &Context = CGM.getContext(); - const uint64_t CharWidth = Context.getCharWidth(); - uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars); - if (FieldOffset > NextFieldOffsetInBits) { - // We need to add padding. - CharUnits PadSize = Context.toCharUnitsFromBits( - llvm::alignTo(FieldOffset - NextFieldOffsetInBits, - Context.getTargetInfo().getCharAlign())); + const uint64_t CharWidth = CGM.getContext().getCharWidth(); - AppendPadding(PadSize); - } + // Offset of where we want the first bit to go within the bits of the + // current char. + unsigned OffsetWithinChar = OffsetInBits % CharWidth; + + // We split bit-fields up into individual bytes. Walk over the bytes and + // update them. + for (CharUnits OffsetInChars = Context.toCharUnitsFromBits(OffsetInBits); + /**/; ++OffsetInChars) { + // Number of bits we want to fill in this char. + unsigned WantedBits = + std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar); + + // Get a char containing the bits we want in the right places. The other + // bits have unspecified values. + llvm::APInt BitsThisChar = Bits; + if (BitsThisChar.getBitWidth() < CharWidth) + BitsThisChar = BitsThisChar.zext(CharWidth); + if (CGM.getDataLayout().isBigEndian()) { + // Figure out how much to shift by. We may need to left-shift if we have + // less than one byte of Bits left. + int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar; + if (Shift > 0) + BitsThisChar.lshrInPlace(Shift); + else if (Shift < 0) + BitsThisChar = BitsThisChar.shl(-Shift); + } else { + BitsThisChar = BitsThisChar.shl(OffsetWithinChar); + } + if (BitsThisChar.getBitWidth() > CharWidth) + BitsThisChar = BitsThisChar.trunc(CharWidth); - uint64_t FieldSize = Field->getBitWidthValue(Context); + if (WantedBits == CharWidth) { + // Got a full byte: just add it directly. + add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar), + OffsetInChars, AllowOverwrite); + } else { + // Partial byte: update the existing integer if there is one. If we + // can't split out a 1-CharUnit range to update, then we can't add + // these bits and fail the entire constant emission. + llvm::Optional FirstElemToUpdate = splitAt(OffsetInChars); + if (!FirstElemToUpdate) + return false; + llvm::Optional LastElemToUpdate = + splitAt(OffsetInChars + CharUnits::One()); + if (!LastElemToUpdate) + return false; + assert(*LastElemToUpdate - *FirstElemToUpdate < 2 && + "should have at most one element covering one byte"); - llvm::APInt FieldValue = CI->getValue(); + // Figure out which bits we want and discard the rest. + llvm::APInt UpdateMask(CharWidth, 0); + if (CGM.getDataLayout().isBigEndian()) + UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits, + CharWidth - OffsetWithinChar); + else + UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits); + BitsThisChar &= UpdateMask; - // Promote the size of FieldValue if necessary - // FIXME: This should never occur, but currently it can because initializer - // constants are cast to bool, and because clang is not enforcing bitfield - // width limits. - if (FieldSize > FieldValue.getBitWidth()) - FieldValue = FieldValue.zext(FieldSize); + if (*FirstElemToUpdate == *LastElemToUpdate || + Elems[*FirstElemToUpdate]->isNullValue() || + isa(Elems[*FirstElemToUpdate])) { + // All existing bits are either zero or undef. + add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar), + OffsetInChars, /*AllowOverwrite*/ true); + } else { + llvm::Constant *&ToUpdate = Elems[*FirstElemToUpdate]; + // In order to perform a partial update, we need the existing bitwise + // value, which we can only extract for a constant int. + auto *CI = dyn_cast(ToUpdate); + if (!CI) + return false; + // Because this is a 1-CharUnit range, the constant occupying it must + // be exactly one CharUnit wide. + assert(CI->getBitWidth() == CharWidth && "splitAt failed"); + assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) && + "unexpectedly overwriting bitfield"); + BitsThisChar |= (CI->getValue() & ~UpdateMask); + ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar); + } + } - // Truncate the size of FieldValue to the bit field size. - if (FieldSize < FieldValue.getBitWidth()) - FieldValue = FieldValue.trunc(FieldSize); + // Stop if we've added all the bits. + if (WantedBits == Bits.getBitWidth()) + break; + + // Remove the consumed bits from Bits. + if (!CGM.getDataLayout().isBigEndian()) + Bits.lshrInPlace(WantedBits); + Bits = Bits.trunc(Bits.getBitWidth() - WantedBits); - NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars); - if (FieldOffset < NextFieldOffsetInBits) { - // Either part of the field or the entire field can go into the previous - // byte. - assert(!Elements.empty() && "Elements can't be empty!"); + // The remanining bits go at the start of the following bytes. + OffsetWithinChar = 0; + } - unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset; + return true; +} - bool FitsCompletelyInPreviousByte = - BitsInPreviousByte >= FieldValue.getBitWidth(); +/// Returns a position within Elems and Offsets such that all elements +/// before the returned index end before Pos and all elements at or after +/// the returned index begin at or after Pos. Splits elements as necessary +/// to ensure this. Returns None if we find something we can't split. +Optional ConstantAggregateBuilder::splitAt(CharUnits Pos) { + if (Pos >= Size) + return Offsets.size(); + + while (true) { + auto FirstAfterPos = std::upper_bound(Offsets.begin(), Offsets.end(), Pos); + if (FirstAfterPos == Offsets.begin()) + return 0; + + // If we already have an element starting at Pos, we're done. + size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1; + if (Offsets[LastAtOrBeforePosIndex] == Pos) + return LastAtOrBeforePosIndex; + + // We found an element starting before Pos. Check for overlap. + if (Offsets[LastAtOrBeforePosIndex] + + getSize(Elems[LastAtOrBeforePosIndex]) <= Pos) + return LastAtOrBeforePosIndex + 1; + + // Try to decompose it into smaller constants. + if (!split(LastAtOrBeforePosIndex, Pos)) + return None; + } +} - llvm::APInt Tmp = FieldValue; +/// Split the constant at index Index, if possible. Return true if we did. +/// Hint indicates the location at which we'd like to split, but may be +/// ignored. +bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) { + NaturalLayout = false; + llvm::Constant *C = Elems[Index]; + CharUnits Offset = Offsets[Index]; + + if (auto *CA = dyn_cast(C)) { + replace(Elems, Index, Index + 1, + llvm::map_range(llvm::seq(0u, CA->getNumOperands()), + [&](unsigned Op) { return CA->getOperand(Op); })); + if (auto *Seq = dyn_cast(CA->getType())) { + // Array or vector. + CharUnits ElemSize = getSize(Seq->getElementType()); + replace( + Offsets, Index, Index + 1, + llvm::map_range(llvm::seq(0u, CA->getNumOperands()), + [&](unsigned Op) { return Offset + Op * ElemSize; })); + } else { + // Must be a struct. + auto *ST = cast(CA->getType()); + const llvm::StructLayout *Layout = + CGM.getDataLayout().getStructLayout(ST); + replace(Offsets, Index, Index + 1, + llvm::map_range( + llvm::seq(0u, CA->getNumOperands()), [&](unsigned Op) { + return Offset + CharUnits::fromQuantity( + Layout->getElementOffset(Op)); + })); + } + return true; + } + + if (auto *CDS = dyn_cast(C)) { + // FIXME: If possible, split into two ConstantDataSequentials at Hint. + CharUnits ElemSize = getSize(CDS->getElementType()); + replace(Elems, Index, Index + 1, + llvm::map_range(llvm::seq(0u, CDS->getNumElements()), + [&](unsigned Elem) { + return CDS->getElementAsConstant(Elem); + })); + replace(Offsets, Index, Index + 1, + llvm::map_range( + llvm::seq(0u, CDS->getNumElements()), + [&](unsigned Elem) { return Offset + Elem * ElemSize; })); + return true; + } + + if (auto *CAZ = dyn_cast(C)) { + CharUnits ElemSize = getSize(C); + assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split"); + replace(Elems, Index, Index + 1, + {getZeroes(Hint - Offset), getZeroes(Offset + ElemSize - Hint)}); + replace(Offsets, Index, Index + 1, {Offset, Hint}); + return true; + } + + if (isa(C)) { + replace(Elems, Index, Index + 1, {}); + replace(Offsets, Index, Index + 1, {}); + return true; + } + + // FIXME: We could split a ConstantInt if the need ever arose. + // We don't need to do this to handle bit-fields because we always eagerly + // split them into 1-byte chunks. - if (!FitsCompletelyInPreviousByte) { - unsigned NewFieldWidth = FieldSize - BitsInPreviousByte; + return false; +} - if (CGM.getDataLayout().isBigEndian()) { - Tmp.lshrInPlace(NewFieldWidth); - Tmp = Tmp.trunc(BitsInPreviousByte); +static llvm::Constant * +EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType, + llvm::Type *CommonElementType, unsigned ArrayBound, + SmallVectorImpl &Elements, + llvm::Constant *Filler); - // We want the remaining high bits. - FieldValue = FieldValue.trunc(NewFieldWidth); - } else { - Tmp = Tmp.trunc(BitsInPreviousByte); +llvm::Constant *ConstantAggregateBuilder::buildFrom( + CodeGenModule &CGM, ArrayRef Elems, + ArrayRef Offsets, CharUnits StartOffset, CharUnits Size, + bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) { + ConstantAggregateBuilderUtils Utils(CGM); + + if (Elems.empty()) + return llvm::UndefValue::get(DesiredTy); + + auto Offset = [&](size_t I) { return Offsets[I] - StartOffset; }; + + // If we want an array type, see if all the elements are the same type and + // appropriately spaced. + if (llvm::ArrayType *ATy = dyn_cast(DesiredTy)) { + assert(!AllowOversized && "oversized array emission not supported"); + + bool CanEmitArray = true; + llvm::Type *CommonType = Elems[0]->getType(); + llvm::Constant *Filler = llvm::Constant::getNullValue(CommonType); + CharUnits ElemSize = Utils.getSize(ATy->getElementType()); + SmallVector ArrayElements; + for (size_t I = 0; I != Elems.size(); ++I) { + // Skip zeroes; we'll use a zero value as our array filler. + if (Elems[I]->isNullValue()) + continue; - // We want the remaining low bits. - FieldValue.lshrInPlace(BitsInPreviousByte); - FieldValue = FieldValue.trunc(NewFieldWidth); + // All remaining elements must be the same type. + if (Elems[I]->getType() != CommonType || + Offset(I) % ElemSize != 0) { + CanEmitArray = false; + break; } + ArrayElements.resize(Offset(I) / ElemSize + 1, Filler); + ArrayElements.back() = Elems[I]; } - Tmp = Tmp.zext(CharWidth); - if (CGM.getDataLayout().isBigEndian()) { - if (FitsCompletelyInPreviousByte) - Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth()); - } else { - Tmp = Tmp.shl(CharWidth - BitsInPreviousByte); - } - - // 'or' in the bits that go into the previous byte. - llvm::Value *LastElt = Elements.back(); - if (llvm::ConstantInt *Val = dyn_cast(LastElt)) - Tmp |= Val->getValue(); - else { - assert(isa(LastElt)); - // If there is an undef field that we're adding to, it can either be a - // scalar undef (in which case, we just replace it with our field) or it - // is an array. If it is an array, we have to pull one byte off the - // array so that the other undef bytes stay around. - if (!isa(LastElt->getType())) { - // The undef padding will be a multibyte array, create a new smaller - // padding and then an hole for our i8 to get plopped into. - assert(isa(LastElt->getType()) && - "Expected array padding of undefs"); - llvm::ArrayType *AT = cast(LastElt->getType()); - assert(AT->getElementType()->isIntegerTy(CharWidth) && - AT->getNumElements() != 0 && - "Expected non-empty array padding of undefs"); - - // Remove the padding array. - NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements()); - Elements.pop_back(); - - // Add the padding back in two chunks. - AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1)); - AppendPadding(CharUnits::One()); - assert(isa(Elements.back()) && - Elements.back()->getType()->isIntegerTy(CharWidth) && - "Padding addition didn't work right"); - } + if (CanEmitArray) { + return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(), + ArrayElements, Filler); + } + + // Can't emit as an array, carry on to emit as a struct. + } + + CharUnits DesiredSize = Utils.getSize(DesiredTy); + CharUnits Align = CharUnits::One(); + for (llvm::Constant *C : Elems) + Align = std::max(Align, Utils.getAlignment(C)); + CharUnits AlignedSize = Size.alignTo(Align); + + bool Packed = false; + ArrayRef UnpackedElems = Elems; + llvm::SmallVector UnpackedElemStorage; + if ((DesiredSize < AlignedSize && !AllowOversized) || + DesiredSize.alignTo(Align) != DesiredSize) { + // The natural layout would be the wrong size; force use of a packed layout. + NaturalLayout = false; + Packed = true; + } else if (DesiredSize > AlignedSize) { + // The constant would be too small. Add padding to fix it. + UnpackedElemStorage.assign(Elems.begin(), Elems.end()); + UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size)); + UnpackedElems = UnpackedElemStorage; + } + + // If we don't have a natural layout, insert padding as necessary. + // As we go, double-check to see if we can actually just emit Elems + // as a non-packed struct and do so opportunistically if possible. + llvm::SmallVector PackedElems; + if (!NaturalLayout) { + CharUnits SizeSoFar = CharUnits::Zero(); + for (size_t I = 0; I != Elems.size(); ++I) { + CharUnits Align = Utils.getAlignment(Elems[I]); + CharUnits NaturalOffset = SizeSoFar.alignTo(Align); + CharUnits DesiredOffset = Offset(I); + assert(DesiredOffset >= SizeSoFar && "elements out of order"); + + if (DesiredOffset != NaturalOffset) + Packed = true; + if (DesiredOffset != SizeSoFar) + PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar)); + PackedElems.push_back(Elems[I]); + SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]); + } + // If we're using the packed layout, pad it out to the desired size if + // necessary. + if (Packed) { + assert((SizeSoFar <= DesiredSize || AllowOversized) && + "requested size is too small for contents"); + if (SizeSoFar < DesiredSize) + PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar)); } + } - Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp); + llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements( + CGM.getLLVMContext(), Packed ? PackedElems : UnpackedElems, Packed); - if (FitsCompletelyInPreviousByte) - return; + // Pick the type to use. If the type is layout identical to the desired + // type then use it, otherwise use whatever the builder produced for us. + if (llvm::StructType *DesiredSTy = dyn_cast(DesiredTy)) { + if (DesiredSTy->isLayoutIdentical(STy)) + STy = DesiredSTy; } - while (FieldValue.getBitWidth() > CharWidth) { - llvm::APInt Tmp; + return llvm::ConstantStruct::get(STy, Packed ? PackedElems : UnpackedElems); +} - if (CGM.getDataLayout().isBigEndian()) { - // We want the high bits. - Tmp = - FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth); - } else { - // We want the low bits. - Tmp = FieldValue.trunc(CharWidth); +void ConstantAggregateBuilder::condense(CharUnits Offset, + llvm::Type *DesiredTy) { + CharUnits Size = getSize(DesiredTy); - FieldValue.lshrInPlace(CharWidth); - } + llvm::Optional FirstElemToReplace = splitAt(Offset); + if (!FirstElemToReplace) + return; + size_t First = *FirstElemToReplace; - Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp)); - ++NextFieldOffsetInChars; + llvm::Optional LastElemToReplace = splitAt(Offset + Size); + if (!LastElemToReplace) + return; + size_t Last = *LastElemToReplace; + + size_t Length = Last - First; + if (Length == 0) + return; - FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth); + if (Length == 1 && Offsets[First] == Offset && + getSize(Elems[First]) == Size) { + // Re-wrap single element structs if necessary. Otherwise, leave any single + // element constant of the right size alone even if it has the wrong type. + auto *STy = dyn_cast(DesiredTy); + if (STy && STy->getNumElements() == 1 && + STy->getElementType(0) == Elems[First]->getType()) + Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]); + return; } - assert(FieldValue.getBitWidth() > 0 && - "Should have at least one bit left!"); - assert(FieldValue.getBitWidth() <= CharWidth && - "Should not have more than a byte left!"); + llvm::Constant *Replacement = buildFrom( + CGM, makeArrayRef(Elems).slice(First, Length), + makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy), + /*known to have natural layout=*/false, DesiredTy, false); + replace(Elems, First, Last, {Replacement}); + replace(Offsets, First, Last, {Offset}); +} - if (FieldValue.getBitWidth() < CharWidth) { - if (CGM.getDataLayout().isBigEndian()) { - unsigned BitWidth = FieldValue.getBitWidth(); +//===----------------------------------------------------------------------===// +// ConstStructBuilder +//===----------------------------------------------------------------------===// - FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth); - } else - FieldValue = FieldValue.zext(CharWidth); - } +class ConstStructBuilder { + CodeGenModule &CGM; + ConstantEmitter &Emitter; + ConstantAggregateBuilder &Builder; + CharUnits StartOffset; - // Append the last element. - Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), - FieldValue)); - ++NextFieldOffsetInChars; -} +public: + static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, + InitListExpr *ILE, QualType StructTy); + static llvm::Constant *BuildStruct(ConstantEmitter &Emitter, + const APValue &Value, QualType ValTy); + static bool UpdateStruct(ConstantEmitter &Emitter, + ConstantAggregateBuilder &Const, CharUnits Offset, + InitListExpr *Updater); -void ConstStructBuilder::AppendPadding(CharUnits PadSize) { - if (PadSize.isZero()) - return; +private: + ConstStructBuilder(ConstantEmitter &Emitter, + ConstantAggregateBuilder &Builder, CharUnits StartOffset) + : CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder), + StartOffset(StartOffset) {} - llvm::Type *Ty = CGM.Int8Ty; - if (PadSize > CharUnits::One()) - Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity()); + bool AppendField(const FieldDecl *Field, uint64_t FieldOffset, + llvm::Constant *InitExpr, bool AllowOverwrite = false); - llvm::Constant *C = llvm::UndefValue::get(Ty); - Elements.push_back(C); - assert(getAlignment(C) == CharUnits::One() && - "Padding must have 1 byte alignment!"); + bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst, + bool AllowOverwrite = false); - NextFieldOffsetInChars += getSizeInChars(C); -} + bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, + llvm::ConstantInt *InitExpr, bool AllowOverwrite = false); -void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) { - assert(NextFieldOffsetInChars <= RecordSize && - "Size mismatch!"); + bool Build(InitListExpr *ILE, bool AllowOverwrite); + bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase, + const CXXRecordDecl *VTableClass, CharUnits BaseOffset); + llvm::Constant *Finalize(QualType Ty); +}; - AppendPadding(RecordSize - NextFieldOffsetInChars); -} +bool ConstStructBuilder::AppendField( + const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst, + bool AllowOverwrite) { + const ASTContext &Context = CGM.getContext(); -void ConstStructBuilder::ConvertStructToPacked() { - SmallVector PackedElements; - CharUnits ElementOffsetInChars = CharUnits::Zero(); + CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset); - for (unsigned i = 0, e = Elements.size(); i != e; ++i) { - llvm::Constant *C = Elements[i]; + return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite); +} - CharUnits ElementAlign = CharUnits::fromQuantity( - CGM.getDataLayout().getABITypeAlignment(C->getType())); - CharUnits AlignedElementOffsetInChars = - ElementOffsetInChars.alignTo(ElementAlign); +bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars, + llvm::Constant *InitCst, + bool AllowOverwrite) { + return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite); +} - if (AlignedElementOffsetInChars > ElementOffsetInChars) { - // We need some padding. - CharUnits NumChars = - AlignedElementOffsetInChars - ElementOffsetInChars; +bool ConstStructBuilder::AppendBitField( + const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI, + bool AllowOverwrite) { + uint64_t FieldSize = Field->getBitWidthValue(CGM.getContext()); + llvm::APInt FieldValue = CI->getValue(); - llvm::Type *Ty = CGM.Int8Ty; - if (NumChars > CharUnits::One()) - Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity()); + // Promote the size of FieldValue if necessary + // FIXME: This should never occur, but currently it can because initializer + // constants are cast to bool, and because clang is not enforcing bitfield + // width limits. + if (FieldSize > FieldValue.getBitWidth()) + FieldValue = FieldValue.zext(FieldSize); - llvm::Constant *Padding = llvm::UndefValue::get(Ty); - PackedElements.push_back(Padding); - ElementOffsetInChars += getSizeInChars(Padding); - } + // Truncate the size of FieldValue to the bit field size. + if (FieldSize < FieldValue.getBitWidth()) + FieldValue = FieldValue.trunc(FieldSize); - PackedElements.push_back(C); - ElementOffsetInChars += getSizeInChars(C); + return Builder.addBits(FieldValue, + CGM.getContext().toBits(StartOffset) + FieldOffset, + AllowOverwrite); +} + +static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter, + ConstantAggregateBuilder &Const, + CharUnits Offset, QualType Type, + InitListExpr *Updater) { + if (Type->isRecordType()) + return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater); + + auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type); + if (!CAT) + return false; + QualType ElemType = CAT->getElementType(); + CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType); + llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType); + + llvm::Constant *FillC = nullptr; + if (Expr *Filler = Updater->getArrayFiller()) { + if (!isa(Filler)) { + FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType); + if (!FillC) + return false; + } } - assert(ElementOffsetInChars == NextFieldOffsetInChars && - "Packing the struct changed its size!"); + unsigned NumElementsToUpdate = + FillC ? CAT->getSize().getZExtValue() : Updater->getNumInits(); + for (unsigned I = 0; I != NumElementsToUpdate; ++I, Offset += ElemSize) { + Expr *Init = nullptr; + if (I < Updater->getNumInits()) + Init = Updater->getInit(I); - Elements.swap(PackedElements); - LLVMStructAlignment = CharUnits::One(); - Packed = true; + if (!Init && FillC) { + if (!Const.add(FillC, Offset, true)) + return false; + } else if (!Init || isa(Init)) { + continue; + } else if (InitListExpr *ChildILE = dyn_cast(Init)) { + if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType, + ChildILE)) + return false; + // Attempt to reduce the array element to a single constant if necessary. + Const.condense(Offset, ElemTy); + } else { + llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType); + if (!Const.add(Val, Offset, true)) + return false; + } + } + + return true; } -bool ConstStructBuilder::Build(InitListExpr *ILE) { +bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) { RecordDecl *RD = ILE->getType()->getAs()->getDecl(); const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); - unsigned FieldNo = 0; + unsigned FieldNo = -1; unsigned ElementNo = 0; // Bail out if we have base classes. We could support these, but they only @@ -378,10 +671,11 @@ if (CXXRD->getNumBases()) return false; - for (RecordDecl::field_iterator Field = RD->field_begin(), - FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { + for (FieldDecl *Field : RD->fields()) { + ++FieldNo; + // If this is a union, skip all the fields that aren't being initialized. - if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field) + if (RD->isUnion() && ILE->getInitializedFieldInUnion() != Field) continue; // Don't emit anonymous bitfields, they just affect layout. @@ -390,23 +684,48 @@ // Get the initializer. A struct can include fields without initializers, // we just use explicit null values for them. - llvm::Constant *EltInit; + Expr *Init = nullptr; if (ElementNo < ILE->getNumInits()) - EltInit = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++), - Field->getType()); - else - EltInit = Emitter.emitNullForMemory(Field->getType()); + Init = ILE->getInit(ElementNo++); + if (Init && isa(Init)) + continue; + + // When emitting a DesignatedInitUpdateExpr, a nested InitListExpr + // represents additional overwriting of our current constant value, and not + // a new constant to emit independently. + if (AllowOverwrite && + (Field->getType()->isArrayType() || Field->getType()->isRecordType())) { + if (auto *SubILE = dyn_cast(Init)) { + CharUnits Offset = CGM.getContext().toCharUnitsFromBits( + Layout.getFieldOffset(FieldNo)); + if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset, + Field->getType(), SubILE)) + return false; + // If we split apart the field's value, try to collapse it down to a + // single value now. + Builder.condense(StartOffset + Offset, + CGM.getTypes().ConvertTypeForMem(Field->getType())); + continue; + } + } + llvm::Constant *EltInit = + Init ? Emitter.tryEmitPrivateForMemory(Init, Field->getType()) + : Emitter.emitNullForMemory(Field->getType()); if (!EltInit) return false; if (!Field->isBitField()) { // Handle non-bitfield members. - AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit); + if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit, + AllowOverwrite)) + return false; } else { // Otherwise we have a bitfield. if (auto *CI = dyn_cast(EltInit)) { - AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI); + if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI, + AllowOverwrite)) + return false; } else { // We are trying to initialize a bitfield with a non-trivial constant, // this must require run-time code. @@ -444,7 +763,8 @@ llvm::Constant *VTableAddressPoint = CGM.getCXXABI().getVTableAddressPointForConstExpr( BaseSubobject(CD, Offset), VTableClass); - AppendBytes(Offset, VTableAddressPoint); + if (!AppendBytes(Offset, VTableAddressPoint)) + return false; } // Accumulate and sort bases, in order to visit them in address order, which @@ -493,93 +813,33 @@ if (!Field->isBitField()) { // Handle non-bitfield members. - AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit); + if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, + EltInit)) + return false; } else { // Otherwise we have a bitfield. - AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, - cast(EltInit)); + if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, + cast(EltInit))) + return false; } } return true; } -llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) { - RecordDecl *RD = Ty->getAs()->getDecl(); - const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); - - CharUnits LayoutSizeInChars = Layout.getSize(); - - if (NextFieldOffsetInChars > LayoutSizeInChars) { - // If the struct is bigger than the size of the record type, - // we must have a flexible array member at the end. - assert(RD->hasFlexibleArrayMember() && - "Must have flexible array member if struct is bigger than type!"); - - // No tail padding is necessary. - } else { - // Append tail padding if necessary. - CharUnits LLVMSizeInChars = - NextFieldOffsetInChars.alignTo(LLVMStructAlignment); - - if (LLVMSizeInChars != LayoutSizeInChars) - AppendTailPadding(LayoutSizeInChars); - - LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment); - - // Check if we need to convert the struct to a packed struct. - if (NextFieldOffsetInChars <= LayoutSizeInChars && - LLVMSizeInChars > LayoutSizeInChars) { - assert(!Packed && "Size mismatch!"); - - ConvertStructToPacked(); - assert(NextFieldOffsetInChars <= LayoutSizeInChars && - "Converting to packed did not help!"); - } - - LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment); - - assert(LayoutSizeInChars == LLVMSizeInChars && - "Tail padding mismatch!"); - } - - // Pick the type to use. If the type is layout identical to the ConvertType - // type then use it, otherwise use whatever the builder produced for us. - llvm::StructType *STy = - llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(), - Elements, Packed); - llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty); - if (llvm::StructType *ValSTy = dyn_cast(ValTy)) { - if (ValSTy->isLayoutIdentical(STy)) - STy = ValSTy; - } - - llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements); - - assert(NextFieldOffsetInChars.alignTo(getAlignment(Result)) == - getSizeInChars(Result) && - "Size mismatch!"); - - return Result; -} - -llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, - ConstExprEmitter *ExprEmitter, - llvm::Constant *Base, - InitListExpr *Updater, - QualType ValTy) { - ConstStructBuilder Builder(Emitter); - if (!Builder.Build(ExprEmitter, Base, Updater)) - return nullptr; - return Builder.Finalize(ValTy); +llvm::Constant *ConstStructBuilder::Finalize(QualType Type) { + RecordDecl *RD = Type->getAs()->getDecl(); + llvm::Type *ValTy = CGM.getTypes().ConvertType(Type); + return Builder.build(ValTy, RD->hasFlexibleArrayMember()); } llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, InitListExpr *ILE, QualType ValTy) { - ConstStructBuilder Builder(Emitter); + ConstantAggregateBuilder Const(Emitter.CGM); + ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero()); - if (!Builder.Build(ILE)) + if (!Builder.Build(ILE, /*AllowOverwrite*/false)) return nullptr; return Builder.Finalize(ValTy); @@ -588,7 +848,8 @@ llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter, const APValue &Val, QualType ValTy) { - ConstStructBuilder Builder(Emitter); + ConstantAggregateBuilder Const(Emitter.CGM); + ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero()); const RecordDecl *RD = ValTy->castAs()->getDecl(); const CXXRecordDecl *CD = dyn_cast(RD); @@ -598,6 +859,12 @@ return Builder.Finalize(ValTy); } +bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter, + ConstantAggregateBuilder &Const, + CharUnits Offset, InitListExpr *Updater) { + return ConstStructBuilder(Emitter, Const, Offset) + .Build(Updater, /*AllowOverwrite*/ true); +} //===----------------------------------------------------------------------===// // ConstExprEmitter @@ -635,7 +902,7 @@ } static llvm::Constant * -EmitArrayConstant(CodeGenModule &CGM, const ConstantArrayType *DestType, +EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType, llvm::Type *CommonElementType, unsigned ArrayBound, SmallVectorImpl &Elements, llvm::Constant *Filler) { @@ -648,10 +915,8 @@ --NonzeroLength; } - if (NonzeroLength == 0) { - return llvm::ConstantAggregateZero::get( - CGM.getTypes().ConvertType(QualType(DestType, 0))); - } + if (NonzeroLength == 0) + return llvm::ConstantAggregateZero::get(DesiredType); // Add a zeroinitializer array filler if we have lots of trailing zeroes. unsigned TrailingZeroes = ArrayBound - NonzeroLength; @@ -672,9 +937,7 @@ } auto *FillerType = - CommonElementType - ? CommonElementType - : CGM.getTypes().ConvertType(DestType->getElementType()); + CommonElementType ? CommonElementType : DesiredType->getElementType(); FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes); Elements.back() = llvm::ConstantAggregateZero::get(FillerType); CommonElementType = nullptr; @@ -941,7 +1204,9 @@ Elts.push_back(C); } - return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts, + llvm::ArrayType *Desired = + cast(CGM.getTypes().ConvertType(ILE->getType())); + return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts, fillC); } @@ -967,80 +1232,24 @@ return nullptr; } - llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base, - InitListExpr *Updater, - QualType destType) { - if (auto destAT = CGM.getContext().getAsArrayType(destType)) { - llvm::ArrayType *AType = cast(ConvertType(destType)); - llvm::Type *ElemType = AType->getElementType(); - - unsigned NumInitElements = Updater->getNumInits(); - unsigned NumElements = AType->getNumElements(); - - std::vector Elts; - Elts.reserve(NumElements); - - QualType destElemType = destAT->getElementType(); - - if (auto DataArray = dyn_cast(Base)) - for (unsigned i = 0; i != NumElements; ++i) - Elts.push_back(DataArray->getElementAsConstant(i)); - else if (auto Array = dyn_cast(Base)) - for (unsigned i = 0; i != NumElements; ++i) - Elts.push_back(Array->getOperand(i)); - else - return nullptr; // FIXME: other array types not implemented - - llvm::Constant *fillC = nullptr; - if (Expr *filler = Updater->getArrayFiller()) - if (!isa(filler)) - fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType); - bool RewriteType = (fillC && fillC->getType() != ElemType); - - for (unsigned i = 0; i != NumElements; ++i) { - Expr *Init = nullptr; - if (i < NumInitElements) - Init = Updater->getInit(i); - - if (!Init && fillC) - Elts[i] = fillC; - else if (!Init || isa(Init)) - ; // Do nothing. - else if (InitListExpr *ChildILE = dyn_cast(Init)) - Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType); - else - Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType); - - if (!Elts[i]) - return nullptr; - RewriteType |= (Elts[i]->getType() != ElemType); - } - - if (RewriteType) { - std::vector Types; - Types.reserve(NumElements); - for (unsigned i = 0; i != NumElements; ++i) - Types.push_back(Elts[i]->getType()); - llvm::StructType *SType = llvm::StructType::get(AType->getContext(), - Types, true); - return llvm::ConstantStruct::get(SType, Elts); - } - - return llvm::ConstantArray::get(AType, Elts); - } - - if (destType->isRecordType()) - return ConstStructBuilder::BuildStruct(Emitter, this, Base, Updater, - destType); - - return nullptr; - } - llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E, QualType destType) { auto C = Visit(E->getBase(), destType); - if (!C) return nullptr; - return EmitDesignatedInitUpdater(C, E->getUpdater(), destType); + if (!C) + return nullptr; + + ConstantAggregateBuilder Const(CGM); + Const.add(C, CharUnits::Zero(), false); + + if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType, + E->getUpdater())) + return nullptr; + + llvm::Type *ValTy = CGM.getTypes().ConvertType(destType); + bool HasFlexibleArray = false; + if (auto *RT = destType->getAs()) + HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember(); + return Const.build(ValTy, HasFlexibleArray); } llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) { @@ -1106,76 +1315,6 @@ } // end anonymous namespace. -bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter, - llvm::Constant *Base, - InitListExpr *Updater) { - assert(Base && "base expression should not be empty"); - - QualType ExprType = Updater->getType(); - RecordDecl *RD = ExprType->getAs()->getDecl(); - const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD); - const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout( - cast(Base->getType())); - unsigned FieldNo = -1; - unsigned ElementNo = 0; - - // Bail out if we have base classes. We could support these, but they only - // arise in C++1z where we will have already constant folded most interesting - // cases. FIXME: There are still a few more cases we can handle this way. - if (auto *CXXRD = dyn_cast(RD)) - if (CXXRD->getNumBases()) - return false; - - for (FieldDecl *Field : RD->fields()) { - ++FieldNo; - - if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field) - continue; - - // Skip anonymous bitfields. - if (Field->isUnnamedBitfield()) - continue; - - llvm::Constant *EltInit = Base->getAggregateElement(ElementNo); - - // Bail out if the type of the ConstantStruct does not have the same layout - // as the type of the InitListExpr. - if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() || - Layout.getFieldOffset(ElementNo) != - BaseLayout->getElementOffsetInBits(ElementNo)) - return false; - - // Get the initializer. If we encounter an empty field or a NoInitExpr, - // we use values from the base expression. - Expr *Init = nullptr; - if (ElementNo < Updater->getNumInits()) - Init = Updater->getInit(ElementNo); - - if (!Init || isa(Init)) - ; // Do nothing. - else if (InitListExpr *ChildILE = dyn_cast(Init)) - EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE, - Field->getType()); - else - EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType()); - - ++ElementNo; - - if (!EltInit) - return false; - - if (!Field->isBitField()) - AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit); - else if (llvm::ConstantInt *CI = dyn_cast(EltInit)) - AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI); - else - // Initializing a bitfield with a non-trivial constant? - return false; - } - - return true; -} - llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C, AbstractState saved) { Abstract = saved.OldValue; @@ -1988,7 +2127,9 @@ return llvm::ConstantAggregateZero::get(AType); } - return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts, + llvm::ArrayType *Desired = + cast(CGM.getTypes().ConvertType(DestType)); + return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts, Filler); } case APValue::MemberPointer: Index: cfe/trunk/test/CodeGenCXX/designated-init.cpp =================================================================== --- cfe/trunk/test/CodeGenCXX/designated-init.cpp +++ cfe/trunk/test/CodeGenCXX/designated-init.cpp @@ -0,0 +1,66 @@ +// RUN: %clang_cc1 -std=c++98 -emit-llvm -o - %s -triple x86_64-linux-gnu | FileCheck %s +// RUN: %clang_cc1 -std=c++11 -emit-llvm -o - %s -triple x86_64-linux-gnu | FileCheck %s + +struct A { int x, y[3]; }; +struct B { A a; }; + +// CHECK: @b = global %{{[^ ]*}} { %{{[^ ]*}} { i32 1, [3 x i32] [i32 2, i32 5, i32 4] } } +B b = {(A){1, 2, 3, 4}, .a.y[1] = 5}; + +union U { + int n; + float f; +}; +struct C { + int x; + U u[3]; +}; +struct D { + C c; +}; + +// CHECK: @d1 = {{.*}} { i32 1, [3 x %[[U:.*]]] [%[[U]] { i32 2 }, %[[U]] { i32 5 }, %[[U]] { i32 4 }] } +D d1 = {(C){1, {{.n=2}, {.f=3}, {.n=4}}}, .c.u[1].n = 5}; + +// CHECK: @d2 = {{.*}} { i32 1, { %[[U]], float, %[[U]] } { %[[U]] { i32 2 }, float 5.{{0*}}e+00, %[[U]] { i32 4 } } } +D d2 = {(C){1, 2, 3, 4}, .c.u[1].f = 5}; + +struct Bitfield { + int a : 3; + int b : 4; + int c : 5; +}; +struct WithBitfield { + int n; + Bitfield b; +}; +// CHECK: @bitfield = {{.*}} { i32 1, { i8, i8, [2 x i8] } { i8 42, i8 2, [2 x i8] undef } } +WithBitfield bitfield = {1, (Bitfield){2, 3, 4}, .b.b = 5}; + +struct String { + const char buffer[12]; +}; +struct WithString { + String str; +}; +// CHECK: @string = {{.*}} [12 x i8] c"Hello World\00" } } +WithString string = {(String){"hello world"}, .str.buffer[0] = 'H', .str.buffer[6] = 'W'}; + +struct LargeArray { + int arr[4096]; +}; +struct WithLargeArray { + LargeArray arr; +}; +// CHECK: @large = global { { <{ [11 x i32], [4085 x i32] }> } } { { <{ [11 x i32], [4085 x i32] }> } { <{ [11 x i32], [4085 x i32] }> <{ [11 x i32] [i32 1, i32 2, i32 3, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 10], [4085 x i32] zeroinitializer }> } } +WithLargeArray large = {(LargeArray){1, 2, 3}, .arr.arr[10] = 10}; + +union OverwritePaddingWithBitfield { + struct Padding { unsigned : 8; char c; } padding; + char bitfield : 3; +}; +struct WithOverwritePaddingWithBitfield { + OverwritePaddingWithBitfield a; +}; +// CHECK: @overwrite_padding = global { { i8, i8 } } { { i8, i8 } { i8 3, i8 1 } } +WithOverwritePaddingWithBitfield overwrite_padding = {(OverwritePaddingWithBitfield){1}, .a.bitfield = 3};